One of my steam radiators started giving me some problems with water
spitting out the vent. I changed the vent, and the radiator is pitched
correctly. Still it spat out water.
So I made sure the shut,off valve was good. I even changed it just to
eliminate it as the problem. While I had the radiator removed, I
opened the shut-off valve to make sure no water was coming out, and it
was fine, only steam came out.
So now I decided to flush out my radiator with a hose and noticed a
lot of junk and rust coming out of it. I put everything back and so
far so good. Could the rust and sludge inside the radiator have
caused this? Could the rust have trapped the water inside preventing
it from draining out?
It's a bit odd that changing the vent didn't remedy the problem. The
radiator didn't stop spitting, even for a while after you changed the
The typical cause of spitting steam vents is dirty steam clogging the
vent. There's always a bit of sludge and rust inside an older
radiator, and depending on how tuned your boiler and distribution is,
you might be sending up wet steam with stuff in it. Some of the
recent _new_ radiators I've installed have been pitiful. The amount
of stuff the manufacturer left inside a new radiator was mind
boggling. Lots of iron filings and drilled-out-cast-iron-flash
disks. It's like they're trying to promote rust and sludge.
How's the water color in the sight glass?
Looks fairly clean. The boiler was installed in March last year, so it
was towards the end of the heating season. This is the first full
season that we've been using it. Perhaps the previous boiler was the
culprit for the sludge in the radiator.
Raised and pitched for complete drainage back to the valve, is a
better way I should have said it. I had a floor guy redo alot of
apartments, he removed the radiators, he reinstalled them level and
now I have a big headache, but I never had one spit water so I think
its a bigger issue.
It's single pipe steam. Boiler is not overfilled. And like I said
before, after I put on the new shut-off valve, I turned up the T-stat,
opened the valve without the radiator connected, and waited for the
steam to come up, which it did, with no sign of water, which led me to
beleive the radiator was the culprit.
To get water out of a vent to me means your supply is cooling off to
much by the time it reaches the radiator and has started to condense
instead of being all steam, are your supplys insulated, or the boiler
is overfull, or supplys have settled from house settling [ do you hear
pipes banging], or you need to ask a pro that knows for other ideas.
Radiators develop sags in the middle , put a level on it, I raise the
vent end up by sometimes 1/2" or more with shims.
I've only seen one steam heat system, I think it was a two pipe system.
When they installed a new boiler the pipes would bang away. I was
told that is normal. Is it?
The old boiler was coal converted to oil and sprang leaks all the time.
It would put out the oil burner and flood the boiler room. It never
really got any pressure. When he got the new one his heating bill was
cut by about 80%. Paid for itself in 2 years.
Banging is water trapped that wont allow steam or condensate to move
freely away and back to the boiler. Old houses that settle unevenly
have this happen. The steam supply and return are not installed level,
there is supposed to be a pitch through out the mains to allow for
condensate draining. A low point will collect water. Insulation of
pipes can help reduce it.
A good place for asking questions about steam heat in particular is
http://heatinghelp.com . Also, there is a book for sale there called, "We
Got Steam Heat!" that I bought and I found helpful. I bought a property
with a one pipe steam heating system, and I needed a crash course in steam
One thing I learned is to keep the pressure in the system set low. Setting
the pressure higher doesn't result in more or better heat -- it results in
less heat and more problems, including excess water condensation, banging
pipe noises, etc. I also learned to open the blow down valve and drain
about a gallon of hot water from the system (until it begins to run clean)
about once every two weeks. Apparently, the previous owners of my system
never kept the system clean so I had to drain mine once a week or more for a
while in the beginning to help clean it out.
You actualy get better heat at 3/4 lb steam than 5 lb and save the
boiler from developing leaks. If you want to hear real pros state this
and get the best reading material www.heatinghelp.com and Dan Holihans
books are the best. I have steam, its a pain in the ass to balance and
Curious, What kind of pressure are you running?
HVAC, Steam and
closed loop Hydronic heating.
In the service field for 25 years.
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